This invention relates to an appliance for oral hygiene comprising a hand-held unit and a base unit, wherein the base unit accommodates an electrically powered device and the hand-held unit is connected to the base unit by means of electrical conductors. Arranged on the hand-held unit is an operating means for varying operating parameters of the electrically powered device. An oral hygiene appliance constructed in this manner is already known from DE-A1 30 36 781 (issued from the international application Publication No. WO 80/01873). Depending on the tool attached thereto, the hand-held unit of this known oral hygiene appliance is suitable for use as either a toothbrush or a water jet, being connected to the base unit by means of a hose having at least three electrical conductors embedded in the hose wall. Depending on whether a toothbrush or a jet attachment is affixed to the hand-held unit, either a first driving mechanism for moving the electric toothbrush or a second driving mechanism for a pump producing a predetermined water pressure is actuated. By means of an operating means arranged on the hand-held unit, the oral hygiene appliance is adapted to be turned on or off.
Especially if the oral hygiene appliance is used as an oral irrigating apparatus, an actuator is conventionally required on the base unit enabling the pressure of the stream of water discharged from the nozzle to be adjusted to meet individual user requirements. As a rule, the user will adjust the jet pressure on the base unit to a setting suited to his or her personal or medical needs before starting the tooth cleansing action. However, during cleansing, the situation may frequently occur that the user is unable to dislodge stubborn food particles from the interproximal spaces at the predetermined pressure setting of the nozzle. The user is thus obliged to temporarily increase the jet pressure on the base unit, for example, by increasing the rotational speed of the pump, reducing it subsequently to a comfortable value after the stubborn food particles have been removed.
It is an object of the present invention to simplify a variation of operating parameters of the oral hygiene appliance in order to thus facilitate and improve the manipulation of the oral hygiene appliance. In particular, embodiments of the present invention are aimed to permit an adjustment of operating parameters of the oral hygiene appliance by means of single-hand control of an operating means provided on the hand-held unit of the oral hygiene appliance. It is a further object to provide an operating means that is easy to clean for its special usage in oral hygiene appliances and is of high reliability in operation. Finally, it is desirable to provide a minimum possible number of electrical conductors between the hand-held unit and the base unit of the oral hygiene appliance. Particularly when the present invention is employed in oral irrigating apparatus in which the electrical conductors are preferably accommodated in the wall of the water supply hose between the base unit and the hand-held unit, the use of a minimum possible number of electrical conductors affords advantages in respect of manufacture, durability and cost of the electrically conducting hose.